If Mitt Romney thought he could make it through the race for the Republican presidential nomination without having to appeal to the party’s theo-con extremists, he was sorely mistaken. In order to secure the Michigan primary win that at least temporarily renewed his candidacy, Romney had to start ranting about how Barack Obama was attacking “religious liberty…because of the people the president hangs around with, and their agenda, their secular agenda.” The former Massachusetts governor even ripped the Obama team for fighting “against religion.”

The “religious liberty” Romney referred to was a newly discovered “constitutional right” to deny women access to contraceptives. The son of Lenore Romney, who ran for the Senate in 1970 as a reproductive rights champion, was not just abandoning positions he once said he learned from his mom. He was framing that abandonment as part of an embrace of the new GOP orthodoxy that says religious groups should define the national agenda on issues ranging from education to healthcare policy.

It was a far cry from the Mitt Romney of 2007, who in an attempt to echo John F. Kennedy’s 1960 speech in favor of church-state separation (and to dispel wariness about his Mormonism as effectively as Kennedy did about his Catholicism), explained that “we separate church and state affairs in this country, and for good reason.” More and more, the formerly pro-choice social liberal has been sounding like Pat Robertson in 1988 or Gary Bauer in 2000, candidates who tried to rally the party’s evangelical base against more rational Republicans.

For Romney, there is no choice. The party he joined as a Massachusetts moderate has ceased to be. This is no longer the GOP of patricians like George Romney or even George H.W. Bush, or of Western individualists like Barry Goldwater, Ronald Reagan or even John McCain—all of whom maintained at least a measure of secularism in a party that has for decades been under assault by the likes of Phyllis Schlafly, Jerry Falwell and Ralph Reed.

It is no secret that the GOP has been veering rightward on “cultural issues” since the mid-1970s, a pattern that ultimately led Goldwater to warn that if “these preachers get control of the party…it’s going to be a terrible damn problem.” Yet it was not until 2012 that advocacy for social conservatism gave way to open disdain for church-state separation. As National Organization for Women president Terry O’Neill puts it, the GOP “crazy train” is leaving the station. And Romney is on it.

Mitt is not the engineer. Rick Santorum grabbed the throttle in February with a series of remarks that culminated in a declaration that Kennedy’s 1960 speech made him ill. Asked about JFK’s historic address, which said that “no public official either requests or accepts instructions on public policy from the pope, the National Council of Churches or any other ecclesiastical source,” Santorum grimaced and said the very idea of preventing religious influence on public policy “makes you throw up.”

But Santorum is not just attacking past presidents. He’s got a doctrinal dispute going with the current one. Obama’s Christianity is a “phony theology,” says the former Pennsylvania senator. Unlike McCain in 2008, Santorum does not challenge supporters who suggest that Obama might be Islam’s Manchurian candidate. And like the Rev. Franklin Graham, Santorum embraces the creepy wordplay that answers questions about the president’s faith by allowing that “he has said he is a Christian.” That’s wink-and-nod talk in a party where primaries and especially caucuses are decided with increasing frequency by evangelical cadres who demand ever more doctrinaire stances from candidates. One-third of delegates to the 2008 convention identified as right-wing evangelicals, and their numbers are certain to rise.

Newt Gingrich, whose appeal remains relatively steady in Sun Belt states, is every bit as “out there” as Santorum. He has kept his campaign going not just with financial support from a Vegas gambling kingpin but in close alliance with so-called Christian Dominionists like Dutch Sheets, who make no secret of their desire to raise armies of “warriors that are ready to do whatever it takes to bring forth [God’s] kingdom rule in the earth.”

No wonder Romney is veering right. Political parties evolve. Candidates for whom winning matters evolve with them. So now, in a country founded on the principle of “no religious tests,” Romney is promising that he will choose a vice president and Supreme Court justices who will meet the new standards of a party that seems to think the Constitution is the third book of Michele Bachmann’s Bible.

If Mitt Romney claws his way to the nomination, he will not run in the tradition of his father’s responsible Republicanism, let alone of the first republicans who rejected the divine right of kings, banned religious tests, recognized that America was not founded as a Christian nation and conceived a wall of separation between church and state that has served the nation well for more than two centuries.